#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int q;
    cin>>q;
    while(q--)
    {
        int n;
        cin>>n;
        int x[10],y[10];
        int minx = 100000, maxx = -100000, miny = 100000, maxy = -100000;
        for(int i=0;i<n;i++)
        {
            cin>>x[i]>>y[i]; 
            if(x[i] < minx)
                minx = x[i];
            if(x[i] > maxx)
                maxx = x[i];
            if(y[i] < miny)
                miny = y[i];
            if(y[i] > maxy)
                maxy = y[i];
        }
        
        int flag = 1;
        for(int i=0;i<n;i++){
           if(!(x[i] == minx || x[i] == maxx || y[i] == miny || y[i] == maxy))
               flag = 0;
        }
        if(flag == 1)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}